Now is a strange time to be watching The War, Ken Burns's 14-hour recounting of America's involvement in the second world war. Away from the television set, another war rages on mindlessly, ignored by most Americans as a distant background clamour not yet loud enough to disturb the fiesta. Another war may soon be upon us, if the 10 or 11 men who started the last one get their way, and if the public and its craven political representatives can once again be stampeded into it in time for the 2008 presidential election.

Set against the cynicism and geopolitical myopia of contemporary Washington, the "Good War" as elucidated by Burns - America's foremost "respectable" mainstream documentarian, a finder of rare and stirring footage, and an impeccable liberal centrist - must inevitably seem like a saintly and noble endeavour. The Greatest Generation had the Good War, of which they were rightly proud; the hippies had the Bad War, of which they were rightly ashamed; this luckless generation has the Stupid War, and we hardly care it's happening.

Burns, for all his flaws - his parochial, insular, almost solipsitically American perspective, and his tendency towards easy lachrymosity - is alive to the differences between then and now, this war and that, although he subtly underplays them. The first episode of The War is called, with a hint of sharp rebuke to the architects of preemptive invasion, A Necessary War.

Each time Burns tackles one of his panoramic American subjects - the civil war, baseball, jazz - the prestige attached to his name, the expense of his projects, and their association with the Public Broadcasting System all guarantee that his version of the nation's galvanising events will soon enough become accepted history. Until the next talented revisionist happens along in another 20 years. The old veneer of illusions is sandblasted away, and another is painted over in its place.

Burns is arriving late to this bout of revisionism, though. The War comes a decade after Saving Private Ryan and six years after Band of Brothers (Tom Hanks is involved in all three). Like them, its insights, its visuals and its lessons learned are refracted through the lens of the Vietnam war. That war was not censored, as the second world war and Iraq have been, and colour television in the 1960s made it impossible to hide the bloodshed that post-1945 film-makers had never shown, but which post-Vietnam film-makers would not avoid. Hence, The War contains unpalatable shots (many in colour) of horribly mangled corpses covering entire fields, shocking us at first, then making us wonder where the similar images are from Iraq.

Yet certain aspects of The War perfectly encapsulate the same middle-of-the-road liberal-American complacency and insularity that is currently hamstringing the Democrats in Congress. Focusing on men and women from four medium-sized American towns, The War is a stunningly insular work, featuring not one interview with an enemy or an ally, with a German, a Japanese, an Italian, a Briton, a Frenchman, a Canadian or a Russian. Brief voiceovers bring us up to date, but the focus is entirely on Americans, sometimes making the war feel like some gigantic national exercise in group therapy. Thankfully, there is relatively little crowing about how America saved the world for democracy (with a racially segregated army, no less). That would be distasteful now that the last droplets of the prestige America had rightly earned by 1945 have been wasted in the sands of the Middle East. Nowhere in The War is there any sense of the infinitely greater, bloodier and more decisive conflict on the Eastern Front, or of the sickening irony, agreed on by a growing body of historians, that the man who really saved democracy was the man who loathed it the most: Joseph Stalin.

"America is hard to see," wrote Robert Frost. But in The War, and in Washington, the rest of the world is completely invisible, and completely irrelevant.